Air circulating system



Aug. 16, 1938. PERSONS 2,12?,46

AIR CIRCULATING SYSTEM Filed Dec. 17, 1934 Patented Aug. 16, 1938 PATENT OFFICE AIR CIRCULATING SYSTEM Lawrence M. Persons, Des Moines, Iowa, assignor to Penn Electric Switch 00., Des Moines, Iowa, a corporation of Iowa Application December 17, 1934, Serial No. 757,884

1 Claim.

An object of my invention is to provide an air circulating system especially adapted for a room cooler installation, having automatic but simple, durable and inexpensive means for freshening the circulated air.

Still a further object is to provide in connection with a room cooler apparatus an automatically operable air flow controller for using outside air' whenever it is cooler than the inside air being circulated.

Still another object is to provide in connection with a room cooler, a fresh air intake and a damper means operable to permit air to be taken in from either the room or through the fresh air intake, a differential thermostat being provided for automatically controlling the damper, depending on whether the fresh air is cooler than the inside air or vice versa.

Still another object is to provide a time controller operable for any selected period of time to cause intake of fresh air, regardless of the position of the differentially operated thermostat.

With these and other objects iniview, my invention consists in the construction, arrangement and combination of the various parts of my air circulating system, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claim, and illustrated in the accompanying drawing, in which:

The figure is a diagrammatic view of a room cooler installation with my air circulating system associated therewith, and includes an electric, diagrammatic. illustration of the circuit for the apparatus.

On the accompanying drawing, I have used the reference numeral ID to indicate generally a room or other enclosure through which air is to be circulated. A register is shown at l2 for discharging air into the room I0, while an outlet register is indicated at 14. The register l4 communicates with an intake l6 of a return duct l8, leading to an air conditioner unit A. The

from the duct l8 and discharges it into a duct 22, which in turn is connected with the register I2.

The air conditioner unit A includes a cooling and dehumidifying mechanism, which will now be briefly described.

A motor 24 drives the blower 20.- Surrounding the blower are a plurality of discs 28 driven by a motor 28. The air taken in by the unit A includes a blower '20, which draws air blower is discharged through the discs before it enters the duct 22.

The discs 26 dip in water 30 contained in a receptacle 32. The water is cooled by a cooling coil 34 connected with a cooling coil 36 for the air stream, and both of these coils being connected with a refrigerant compressor 38. At 40, the condenser of the compressor is shown while at 42, the motor for the compressor is illustrated.

The parts 20 to 42 just described form no part of my present invention and have been but briefly referred to. The unit A and the refrigerating mechanism are disclosed in detail in my copending application, Serial No. 651,521, filed January 13, 1933, Patent No. 2,054,039. Suitable controls, of course, are provided for the motors 24, 28 and 42 in accordance with the requirements for circulation, dehumidification of the circulated air and refrigeration for the cooling coils 34 and 36 respectively, but these are not shown on the drawing.

My present invention has specifically to do with the apparatus which I will now describe;

A fresh air intake is illustrated at 44. A damper 46 is pivoted at 48 and adapted to normally assume the full line position, so that the air drawn into the duct ill will come through the register I4 and the intake l6, while when in the dotted line position, the air will enter from the outside of the building through the fresh air duct 44.

Any suitable mechanism may be used for operating the damper 46 and automatically controlling its position.

I have shown a heat motor 3 comprising an expansible bellows 50, a boiler 52, and a resistance or heating element 54, operatively connected with the damper 46. The bellows and boiler are filled with volatile fluid, which will volatilize when the heat element 54 is energized for expanding the bellows. The operative connection mentioned comprises a lever 56 pivoted at 58 and having one end connected with the bellows 50, while its other end is connected by a link 60 with an arm 62 of the damper 46.

When the heating element is de-energized, the parts will assume the full line position while when it is energized, they will assume the dotted line position.

For controlling the energization of the heater 54 automatically, I provide a differential thermostat C. It comprises a pair of expansible bellows 64 and 66 operating on opposite sides of a switch arm 68. The bellows 64 has a temperature responsive bulb 10 located in a bulge 12 of the intake it, while the bellows 66 has a temperature responsive bulb 74 located in a bulge ?6 of the fresh air intake ML. The bulge 6 permits air to flow past the bulb i4 when the damper is in the full line position as indicated by the arrow Na, and likewise the bulge i2 permits air as indicated by the arrow 10a to flow past the bulb 10 when the damper 46 is in the dotted line position.

When the temperatures affecting the bulbs W and M are equal, the switch arm 68 will remain in the open circuit position. Also when the temperature affecting the bulb M is greater than the temperature affecting the bulb 10, the switch will remain open. When the temperature affecting the bulb 70 is greater than that affecting the bulb 15, however, the switch will close, whereupon the position of the damper 46 will be changed, due to the operation of the damper motor B.

The circuit when the switch arm 68 is in the closed position can be traced from one current supply wire D through contacts 69 of the differential thermostat C and then through a wire d and the heat coil 54 to the other current supply wire indicated at E. This, of course, will expand the bellows 50, so that the damper 46 will assume its dotted position.

From the foregoing description, it will be obvious that during a normal summer day, recirculation of the air through the room It] will be accomplished and the unit A will cool and dehumidify it. Air recirculated in this manner needs freshening after some 14 or 16 hours period under normal conditions, and sometimes needs freshening oftener than that. By providing the differential thermostat this freshening is accomplished because during the night time, the outside air becomes cooler than the air being circulated through the room. 'I'hereupon the differential thermostat C will close, and thus air would be taken in through the fresh airintake 44 instead of through the intake I6.

This accomplishes two purposes. It freshens the air and it utilizes the cooler outside air to cool the room It], instead of having to use the conditioner unit A for this purpose during the night.

If it so happens that the night is so warm that it does not close the differential thermostat or closes it for a period of time which is of insufiicient length to freshen the air, then it is desirable to manually control the damper 46. This is accomplished by the following described mechanism:

The timing controller F is illustrated, which comprises a disc E8 of insulation having a collector ring Gil. tact with the disc and the collector ring. The disc is normally retained with a projection 84 against a stop 86, by a spring or other suitable mechanism, but can be manually rotated clockwise, whereupon the spring will return it to its initial position, retarded, however, by suitable clockwork mechanism, such as fully described in my co-pending application, Serial No. 737,059, filed July 26, 1934. Thus the timing controller F can be set for any number of hours or other units of time, the contacts 82 being connected by the collector ring 80 as soon as the projection 86 is moved away from the stop 86, and such connection will continue during the desired period of time.

The contacts 82 when connected with the collector ring 80 supply current from the supply wire D through a wire e to the heating element 54 independent of the differential thermostat C.

This will accordingly change the position of the damper 46, so that fresh air will be taken into the duct I8 during the period of time for which the controller F has been set.

Thus the contingency mentioned can be taken care of by the controller F, or other contingencies such as when there is a gathering in the room Hi, consisting of a considerable number of people, and it is desired therefore to take in fresh air for some desired period of time.

Some changes may be made in the arrangement and construction of the various parts of my system, without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claim, any modified forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

In an air circulating system, a room, air circulating means having an intake and an outlet, each communicating with said room, an auxiliary intake for receiving outside air, a damper for selectively causing air to be taken into said air circulating means from said first or said auxiliary intake, and a controller having two independent elements, one in and thereby responsive to the temperature of the air in one of said intakes and the other in and thereby responsive to the temperature of the air in the outer of said intakes for controlling said damper, and means for causing a small quantity of air to flow through one Contacts 82 are adapted to con- 

